Fix valgrind complaints of uninitialized memory

src/dungeon.c

@@ -490,6 +490,7 @@ struct proto_dungeon *pd;
 
     branch_num = find_branch(dungeons[dgn].dname, pd);
     new_branch = (branch *) alloc(sizeof(branch));
+    (void) memset((genericptr_t)new_branch, 0, sizeof(branch));
     new_branch->next = (branch *) 0;
     new_branch->id = branch_id++;
     new_branch->type = correct_branch_type(&pd->tmpbranch[branch_num]);
@@ -545,6 +546,7 @@ struct proto_dungeon *pd;
 
     pd->final_lev[proto_index] = new_level =
         (s_level *) alloc(sizeof(s_level));
+    (void) memset((genericptr_t)new_level, 0, sizeof(s_level));
     /* load new level with data */
     Strcpy(new_level->proto, tlevel->name);
     new_level->boneid = tlevel->boneschar;

src/engrave.c

@@ -388,6 +388,7 @@ xchar e_type;
     if ((ep = engr_at(x, y)) != 0)
         del_engr(ep);
     ep = newengr(strlen(s) + 1);
+    (void) memset((genericptr_t)ep, 0, sizeof(struct engr));
     ep->nxt_engr = head_engr;
     head_engr = ep;
     ep->engr_x = x;

src/objnam.c

@@ -2516,7 +2516,7 @@ struct obj *no_wish;
     int halfeaten, mntmp, contents;
     int islit, unlabeled, ishistoric, isdiluted, trapped;
     int tmp, tinv, tvariety;
-    int wetness, gsize;
+    int wetness, gsize = 0;
     struct fruit *f;
     int ftype = context.current_fruit;
     char fruitbuf[BUFSZ];

src/options.c

@@ -5496,6 +5496,7 @@ struct fruit *replace_fruit;
         return rnd(127);
 
     f = newfruit();
+    (void) memset((genericptr_t)f, 0, sizeof(struct fruit));
     copynchars(f->fname, *altname ? altname : str, PL_FSIZ - 1);
     f->fid = ++highest_fruit_id;
     /* we used to go out of our way to add it at the end of the list,

src/timeout.c

@@ -1533,6 +1533,7 @@ anything *arg;
         panic("start_timer");
 
     gnu = (timer_element *) alloc(sizeof(timer_element));
+    (void) memset((genericptr_t)gnu, 0, sizeof(timer_element));
     gnu->next = 0;
     gnu->tid = timer_id++;
     gnu->timeout = monstermoves + when;

src/trap.c

@@ -337,6 +337,7 @@ int x, y, typ;
     } else {
         oldplace = FALSE;
         ttmp = newtrap();
+        (void) memset((genericptr_t)ttmp, 0, sizeof(struct trap));
         ttmp->ntrap = 0;
         ttmp->tx = x;
         ttmp->ty = y;